NEO TOOLS 11-267 Mode D'emploi page 8

4.8. Testing Vacuum Operated Heater Taps
Climate control ventilation systems are becoming very common on newer
vehicles and most of the systems use vacuum operated taps to control the
heating modes.
On the majority of makes and models, the system uses vacuum to turn the
heater tap ‚on' . To test these remove the supply line from the tap vacuum
module and connect the CT3258 vacuum tester (fig.11). With the engine at
normal operating temperature locate and feel the heater return hose. With
the heater tap in the ‚off' position, this hose should be cold. Now operate the
vacuum pump to open the tap. The gauge reading must hold. If the tap is in
working order, the return hose will begin to heat. If the hose does not begin
to heat this indicates that the tap is faulty.
4.9. Testing Vacuum Operated Remote Central Locking Systems
Some makes and models use vacuum operated bellows mounted in each
door, to centrally lock and unlock the vehicles doors. These systems use
either manifold vacuum stored in a reservoir for use when the engine is not
running or an electrically driven vacuum pump which operates when the
doors are locked or unlocked. In either system, the CT3258 vacuum tester is
ideal for testing each individual door bellows. To do this, remove the door
trims as required. Remove the vacuum supply lines from the bellows and
attach the CT3258 vacuum tester (fig.12) and operate to apply vacuum to
the bellows. Wait for 30 seconds, no drop on the gauge should be noted.
If the bellows are found to be in order attach the vacuum supply line to
the CT3258 vacuum tester and operate system to test for vacuum supply.
If the vacuum supply does not exist or is low trace back down the lines to
the vacuum supply looking for kinks, restrictions or cracked lines. Repair as
required and retest.
4.10. Testing Automatic Transmission Vacuum Operated Modulator
Valves
Automatic transmissions are normally equipped with a vacuum operated
modulator valve in order for the automatic transmission to detect engine
loads and adjust shift points to suit. The CT3258 vacuum tester can be
used to test both that the modulation valve diaphragm is serviceable and
also to simulate varying engine loads so modulator pressure readings can
be recorded. To test the modulator valve diaphragm remove the vacuum
supply line from the valve and attach the CT3258 vacuum tester. Operate
the vacuum pump until approximately 15 inHg is achieved and monitor the
gauge reading for approximately 30 seconds. No vacuum drop should be
noted. To check modulator pressure readings attach a pressure gauge to the
appropriate port on the transmission. Remove the vacuum supply line from
the modulator and attach theCT3258 vacuum tester (fig.13). Start and run
the engine and apply vacuum pressures. Monitor readings and confirm that
these are in conformance with manufacturer specifications.
4.11. BRAKING SYSTEMS
Testing Brake Servo Diaphragm
Remove vacuum supply line from brake servo fitting. Attach CT3258
vacuum tester to vacuum supply port on servo (fig.14). Operate pump
to create approximately 15 inHg of vacuum and wait for 30 seconds. No
vacuum drop should be observed on the gauge reading. If the vacuum
drops this indicates that the brake servo diaphragm is faulty. In this case the
servo should be removed for overhaul by an authorised repairer or replaced.
All manuals and user guides at all-guides.com
Brake Bleeding - Assembly of Brake Bleeder Kit
Ensure that the vacuum pump is connected to the brake bleeder reservoir
in accordance with the assembly diagram (fig.15). Failure to do so will result
in brake fluid being drawn into the vacuum pump.
Brake Bleeding Procedure.
WARNING! Familiarise yourself with the hazards of brake fluid - read
manufacturer's instructions on the container. Do not touch the vehic-
le's brake pedal whilst bleeding the brakes.
Refer to the specific vehicle manufacturer's instructions for brake bleeding
and wheel sequence procedure before proceeding. If no specific instructions
from the vehicle manufacturer exist, follow the instructions detailed below.
1. Remove the cap of the vehicle's master brake fluid reservoir. If the fluid
level is not at maximum, top it up.
2.
Apply copper grease to the brake bleeding nipples before and after
the brake bleeding procedure to reduce the possibility of seized or
broken nipples when the brakes are next bled.
3. Attach the appropriate size bleeding attachment to the bleed nipple
on the brake calliper of the first wheel, normally nearest to master
brake fluid reservoir.
4. Operate vacuum pump until approximately 21 inHg vacuum is
created.
5.
Open the bleed nipple about a quarter of a turn (fig.16). Allow brake
fluid to be drawn until no air bubbles are visible in the brake fluid in
the clear hose.
6. Tighten the bleed nipple.
7. Remove the attachment from the brake nipple.
8.
Repeat the process as necessary at each wheel.
9. Check the master brake fluid reservoir regularly to ensure that the
level does not drop too far, and top up as necessary.
10. Empty bleeder container regularly and do not allow container
to overfill as brake fluid will be drawn into vacuum pump.
When brake bleeding and/or fluid changing is complete, test the
action of the brake pedal to ensure that the brakes are working
- before attempting to drive the vehicle on the road and test the
vehicle for satisfactory performance of the braking system.
11.
Clean bleeder components ‚with water only' after use.
Clutch Bleeding Procedure.
Refer to the relevant vehicle manufacturer's instructions for clutch bleeding
procedure. If no specific instructions from the vehicle manufacturer exist,
follow the same basic procedure as the brake bleeding instructions above.
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